/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.druid.query;

import com.google.common.annotations.VisibleForTesting;
import org.apache.druid.guice.LazySingleton;

@LazySingleton
public class DefaultGenericQueryMetricsFactory implements GenericQueryMetricsFactory
{
  private static final GenericQueryMetricsFactory INSTANCE =
      new DefaultGenericQueryMetricsFactory();

  /**
   * Should be used only in tests, directly or indirectly (e. g. in {@link
   * org.apache.druid.query.search.SearchQueryQueryToolChest#SearchQueryQueryToolChest}).
   */
  @VisibleForTesting
  public static GenericQueryMetricsFactory instance()
  {
    return INSTANCE;
  }

  @Override
  public QueryMetrics<Query<?>> makeMetrics(Query<?> query)
  {
    DefaultQueryMetrics<Query<?>> queryMetrics = new DefaultQueryMetrics<>();
    queryMetrics.query(query);
    return queryMetrics;
  }

  @Override
  public QueryMetrics<Query<?>> makeMetrics()
  {
    return new DefaultQueryMetrics<>();
  }
}
